1. Field of the Invention
The present invention relates to an evaporative treatment method for an aqueous solution, and more specifically, relates to an aqueous solution evaporative treatment method in which an aqueous solution containing calcium, magnesium, and silica is evaporated by indirect heating.
2. Description of the Related Art
When evaporating an aqueous solution containing impurities such as calcium by indirect heating, scale builds up on the heat transfer surface of a heat exchanger, and the heat transfer coefficient is likely to deteriorate. Accordingly, to date, measures to address this phenomenon have been investigated. For example, Patent Document 1 discloses a waste water treatment method in which sodium carbonate is added to waste water containing calcium and sulfuric acid to precipitate the calcium contained in the waste water as crystals of calcium carbonate, and then the waste water is concentrated through boiling/evaporation by indirect heating.
Patent Document 1: JP-A 2006-305541